Prenylflavonoids: a new class of non-steroidal phytoestrogen (Part 1). Isolation of 8-isopentenylnaringenin and an initial study on its structure-activity relationship - Kitaoka, M; Kadokawa, H; Sugano, M; Ichikawa, K; Taki, M; Takaishi, S; Iijima, Y; Tsutsumi, S; Boriboon, M; Akiyama, T (Planta Med, 2007)